I have a 1994 Ford Explorer with an acceleration issue.?

I have a 1994 Ford Explorer. For the most part it runs decent. However, when I come out of braking or when I am driving it there will be some hesitation when I accelerate. This causes me to have to push harder on the gas making the car do a slight skid. Or, if I am at a light on an incline or something when this happens the car will just roll backwards. Please HELP!!!